This invention relates generally to the field of sprinkler systems for fire protection systems. More particularly, this invention relates to alarm test and drain devices for fire protection sprinkler systems, and specifically to dual-function devices in which the alarm test and drain functions are combined.
Some alarm test devices for sprinkler type fire protection systems combine, into a single device, both a system test function, for testing to ensure that the system is activated and will respond to a real triggering event, namely, a fire, by delivering extinguishing fluid, usually water, to the sprinkler heads; and a system drain function, for draining all of the extinguishing fluid from a xe2x80x9cwetxe2x80x9d, or normally fluid-filled type sprinkler system, such as occurs when the system must be temporarily taken out of service for repairs; or in either a xe2x80x9cwetxe2x80x9d or a xe2x80x9cdryxe2x80x9d system, after the system has been actuated in response to a fire and the system piping is still at least partially filled with residual extinguishing fluid, so as to be able to drain the remaining fluid in order to reset the system. Some apparatus also incorporates gauge glasses or similar observation devices to enable visual inspection of the status of the liquid flow through the system. These combination devices, also known as inspection, test and drain devices, are used to provide a connection for testing the system""s alarm equipment, and are also used to drain sprinkler type fire protection systems.
Certain such combined devices are already known in the art. For example, U.S. Pat. No. 4,741,361 to McHugh for xe2x80x9cValve and Arrangement for Fire Suppression Water Sprinkler Systemxe2x80x9d, U.S. Pat. No. 4,655,078 to Johnson for xe2x80x9cSprinkler Drain and Test Valvexe2x80x9d, and U.S. Pat. No. 4,643,224 to Rung et al for Alarm Test Device for a Sprinkler System, all disclose combined alarm test and drain apparatus.
In the apparatus of both McHugh and Johnson, the sealing element and drain connection are effected by means of a rotary member in the form of a ball, incorporating modifications to a conventional ball valve design. In contrast, the apparatus of Rung et al, although enclosed in a single housing, incorporates two separate valves, one for the purpose of draining the system and the other for allowing flow through a separate test orifice to test for fluid flow as if to a sprinkler head when actuated. Generally, previously known apparatus, especially that requiring two separate valves, has the disadvantage of being bulky or requiring a special orientation or configuration when placed in the system piping, thereby occupying a considerable amount of space, where typically space is very limited.
Accordingly, the present invention provides a combined alarm test and drainage apparatus for use in sprinkler fire protection systems, wherein a single modified valve is used for both the test and drain functions, and which occupies very little space and can easily be connected to the piping of a sprinkler type fire protection system. The apparatus is based on a globe valve and has certain specific modifications for the purposes of draining the system and allowing for flow through a specifically sized orifice under conditions simulating the flow through a sprinkler head having the same orifice size. Fluid flow through the apparatus occurs alternatively under a first set of test actuation conditions in a system alarm test mode of operation of the apparatus, and under a second set of fluid drainage actuation conditions in a system fluid drainage mode of operation of the apparatus. A combination of mechanical and hydraulic forces are utilized to control opening and closing of the valve in both the alarm test and system fluid drainage modes of operation. The mechanical force is provided by a spring and the hydraulic force is provided by a fluid pressure differential. When the apparatus is performing the system alarm test function under the first set of test actuation conditions, the valve opens a first size outlet opening, and when the apparatus is performing the system fluid drainage function under the second set of drainage actuation conditions, the valve opens a second size outlet opening, larger than the first size opening. When the apparatus is in the system alarm test mode of operation, a valve actuation member is positioned to seal the second size opening of the valve, and fluid flows into a fluid chamber through a fluid chamber inlet opening, a fluid chamber outlet opening is unsealed, and fluid flows out through the fluid chamber outlet opening; and when the apparatus is in the system drainage mode of operation, the valve actuation member is moved to unseal the second size opening of the valve.